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Poster Session R
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Basic Study on Orhon – Ongin River Diversion
G. Lakhan-Aasuren, A. Tsetsgee, M. Saandar
Remote Sensing & Geoinformation Center, MGGE, Mongolia
Hiroshi Yamamota, A. Hamamori
International Engineering Research Institute, Tokyo, Japan
Abstract
Orhon-Ongin river basin area in Mongolia, which is located in Gobi area, is rich in mineral resources, such as coal, colored and rare metal. It is also suitable for mining and cattle breeding industries. And for this reason, the area is very important for the Mongolian economy. Rivers and lakes in this area have nearly dried due to climate condition and human activities.
That is why we need to carry out an investigation on the water resources and the recharge and also have an ecological basic study by the using Remote Sensing.
Introduction
The basic study on orhon-ongin river diversion is needed because there is an inherent water shortage which is caused by the climatic conditions of the area. Therefore, it is urgent to conduct geology ecology, etc., before making any concrete decision about the diversion plan.
Study Area
The origin river basin and surrounding area is located in Gobi. The study area is the watershed of Orhon river and ongin river is shown in Figure 1. The study area is 99.,528 km2.
With the help of satellite images an average annual surface and groundwater flow map in the scale 1:1,000,000 was created. By using this map the natural condition of the orhon-ongin river basin was described. Its desert and semi-desert ecosystem is suitable for grazing camels, sheep and goats, which are utilized as material for wool, blankets and other livestock processing. Also, this area is very rich in mineral resources, such as coal, colored and rate metals. The stock breeding and the mining industries contribute not only for the domestic use but also for export. For this reason, the area is very important for the national economy and its development desirable.
However, absolute water shortage due to climate conditions is
impeding such development. Furthermore, some small rivers and lakes in the South Gobi admits surroundings have dried up in the past ten years, and now the areas shows signs of desertification. Especially, ongin river and its inland lake, Ulaan Nuur, have nearly dried up and have seriously influenced the lifestock farming and the life of the residents. To maintain the comfortable life of the residents without the effects of desertification and to further develop the area, is necessary to secure water resources.
The area of the ongin river basin and its surroundings mainly uses groundwater because it is difficult to obtain surface water due to extremely low precipitation. In the Hangai mountain, where the orhon-ongin river has its orngin, the precipitation is 200-325 mm, in the planes 100-200mm and in the Gobi 50 – 100mm. In the warm season, the ground surface becomes extremely hot and causes vertical turbulent air movement. Therefore, some areas receive heavy rain for a short period of time. the main characteristics of the climate in the study area is monsoon rainfall, which occurs between July and August. This area has 4 natural zones because there are geomorphological differences and therefore environmental temperature variation is high. The mean monthly temperature reaches in January a low – 18°C - 20°C compared to a high of +40°C + 45°C in July. Average annual temperatures are:
-for Hangai mountains at 1800m and higher from =1°C to 1°C;
-for Gobi and plane zones at 1500 m from +1°C to +4°C
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